Brexit talks reach 'deadline of deadlines'

Britain must present the European Union with a good offer this week on the terms of its divorce from the bloc, or it will be too late for the EU to prepare for mid-December the start of talks on a future trade deal, a senior EU diplomat says.

"The 'deadline of deadlines' is this week," the diplomat said when asked how much time the EU and Britain have for a deal to ensure the 27 remaining members of the bloc can prepare the opening of trade talks with London at a summit on December 14-15.

As a deal crumbled on Tuesday British Prime Minister Theresa May faced more pressure to soften the EU divorce by keeping Britain in the single market and customs union after Brexit.

The Northern Irish party that props up May's minority government said it was only shown the draft of a deal promising regulatory alignment for both parts of Ireland late on Monday morning and that it had told the government that it was unacceptable.

The Labour Party says one way for alignment to be acceptable is for the whole of the UK to stay in the single market and the customs union.

Nicola Sturgeon, the leader of Scotland's devolved government, and Scottish Conservative leader Ruth Davidson, who has been tipped as a potential future leader, both suggested the UK stay in.